Generally, a hot-key mouse is specially designed for a user to operate by his/her left or right hand according to personal habitual behavior. With reference to FIG. 3, a prior art of a mouse 1′ with hot keys 14′ is designed for a right hand user; the hot keys 14′ are installed at left lateral side of the mouse 1′ near the position to be held by the thumb; on the contrary, a mouse of prior art designed for a left hand user has the hot keys installed on the right lateral side of the mouse. Generally, a conventional hot-key mouse has the hot keys positioned on the left and the right sides of the left and the right mouse buttons 11′ and 12′ of the mouse 1′; whereas each type of mouse has a scroll wheel 13′ installed thereon, the scroll wheel 13′ is a essential accessory to a mouse.